This multidisciplinary study will develop a comprehensive, uniform clinically based and empirically derived and validated nosology of disorders of higher cerebral function in children. This will generate a comprehensive, rational schema for diagnosis, treatment and prognosis which will improve the management of patients, the training of health care providers, and further research into these disorders. Though such a system would seem fundamental to treatment and research within the field of disorders of higher cerebral function in children, there are now no empirically derived and validated criteria for diagnosing between different specific disorders, nor, for that matter, are there generally accepted diagnostic criteria for subtypes within a specific disorder. To date, the pilot effort of this group stands as the only effort in this area. The nosology will be created through the use of an empirical validation methodology. Six major groups will be examined: Speech/Language, Motor Execution, Autism, Calculation, Attention/Activity, and Reading Disabilities. Within each group of disorders, more homogeneous subtypes will be developed. Subject children (N-200 per major group) will receive a Core Battery of medical, cognitive and behavioral measures, as well as an Area-Specific Battery of assessments specific to a particular disorder. A Core Methodology, utilizing an empirical framework, and multivariate classification techniques (cluster analysis), will be utilized across all groups to provide empirical support for hypothesized diagnostic groups. A pilot sample (N=25 per major group) will first confirm a consistent assessment and methodology across all sites and groups. The final nosology, with appropriate guides to users of varying disciplines, will be developed through cooperation of all investigators, in order to provide a unifying structure to the practice and future of this area of child neurology ahd its allied disciplines. The nosology will thereby enhance communications among researchers, promote development of snydrome-specific intervention programs, and, ultimately, facilitate study of the relationship between specific groups and dysfunction of specific brain systems. It will provide the nosologic foundations for investigations into these neurobiological processes, as assessed through new and future neurodiagnostic instrumentation and methodology. This instrumentation, it is hoped, will provide for the further refinement and ultimate validation of this nosology.